Abstract: A device for detecting a pulsating variable by fixed-angle dual sampling with slight filtering in which the pulsating variable is filtered and/or damped in such a manner that a quasi-sinusoidal variation is obtained. The signal thus obtained is a crank-angle-synchronous signal sampled twice per duration of one period. From these two measurement values, a current mean value of the pulsating variable is determined once per duration of the period.

Abstract: The invention is directed to a control circuit for controlling the speed of an electric fuel pump for an internal combustion engine having fuel injection and includes a speed limit-value comparator for controlling the speed or delivery rate of the fuel pump to a value below the minimum speed or delivery rate for a speed of the engine above a specific predetermined limit speed which is impermissibly high. The minimum speed or minimum delivery rate is then the delivery rate which is required for at least building up the system pressure in the fuel injection system.